The Debian packaging of bitlbee-facebook is maintained in git, using
the merging workflow described in dgit-maint-merge(7).  There isn't a
patch queue that can be represented as a quilt series.

A detailed breakdown of the changes is available from their canonical
representation - git commits in the packaging repository.  For
example, to see the changes made by the Debian maintainer in the first
upload of upstream version 1.2.3, you could use:

    % git clone https://git.dgit.debian.org/bitlbee-facebook
    % cd bitlbee-facebook
    % git log --oneline 1.2.3..debian/1.2.3-1 -- . ':!debian'

(If you have dgit, use `dgit clone bitlbee-facebook`, rather than
plain `git clone`.)

A single combined diff, containing all the changes, follows.
--- bitlbee-facebook-1.2.2.orig/.gitignore
+++ bitlbee-facebook-1.2.2/.gitignore
@@ -10,7 +10,6 @@ build-aux
 config.log
 config.status
 configure
-debian
 facebook/facebook-marshal.*
 INSTALL
 libtool
